Suppression of metal catalysis



' tion reactions Patented Apr. 18, 1944 o STATES PATENT OFFlCE.

surrnnssroiv F METAL cA'rALYsIs Joseph. A. Chenicek, Chicago, BL, assignor to Universal Oil Products Company, Chicago, 11]., a corporation of Delaware No Drawing. Application April 8, 1940, Serial No. 328,524

21 Claims.

blefins and somewhat smaller concentrations of other unsaturated olefins.

The function of inhibitors is primarily to minimize or prevent such oxidation reactions and thus keep the motor fuel in satisfactory condition for use in internal combustion engines. They tend to prevent losses in antiknock value which accompanies oxidation of this type of gasoline. Among the materialswhich have been used are various phenolic and amino compounds as well as fractions of wood tar oils, particularly those of hard woods, boiling in the range of approximately 240280 C'., etc., which are usually added to the gasoline in concentrations of approximately 0.001-0.l%, depending upon the efiectiveness of the particular compound used and the gasoline to which it is added.

Although inhibitors are used in both treated and untreated gasolines, it is with the latter type that they find the greatest application. Treated gasolines are those which have been subjected to chemical refining processes such as sulfuric acid, fullers earth and the like, either with or without a sweetening treatment following. Untreated gasolines are those which have received no refinement beyond possibly caustic washing and/or sweetening. The former type of gasoline is usually relatively stable and requires little or no added inhibitor, although the use of inhibitors has been practiced to supplement other refining methods. In the case of untreated gasolines, on the other hand, many of them are unstable and require the protection afforded by'inhibitors to prevent undue deterioration during the time they arein storage.

Practically all gasolines require some form of sweetening treatment in order to improve the odor thereof and produce a product having a negative doctor test. The sodium plumblte or doctor process, as well as the hypochlorite sweetening process, have been used in the past with considerable success. During recent years, the so-called copper sweetening process has been developed in which gasoline is contacted with a copper-containing reagent. As a result of the presence of relatively minor amounts of impurihydrocarbons such as dities in such gasolines, the sweetened gasoline usually contains relatively small amounts of copper compounds which have a catalytic effect on oxidation reactions which may result when the gasoline comes in contact with air. methods have been developed for removing such copper compounds including treatment with alkali or alkaline earth metal sulfides and heavy metal sulfides such as zinc sulfide and the like. In some instances, however, these reagents may Y not be completely effective in removing the copper from the gasoline and as a consequence the gasoline may have a reduced stability and susceptibility to added gasoline gum inhibitors. Moreover, gasolines come in contact with various metals in the course of refining, storage and shipping operations, and this may result in-the gaso-.

line containing minute amounts of such metals as copper, iron, cobalt, nickel ,and the like, which are oxidation catalysts. It is with a method of maticaldehyde with a primary alkanol amine,

either with or without an added gum inhibitor. Compounds of this type are represented by the following general formula:

5 Kbav-w-on H wherein B may be hydrogen or a substituent group hereinafter termed suppressers,.are not necesr sarily exactly equivalent. Furthermore they possess varying degrees of solubility in hydrocarbon distillate which may influence the eiiective- Various.

ness in any given stock. The proper choice of a suppresser for any particular oil will depend upon these factors, and is, in the end, a matter at test.

In some cases the compounds maybe used in the gasoline without added gum inhibitors. This is particularly true when used in connection with straight-run distillates or cracked gasolines which have been refined to an adequate degree oi stabilitymch as by acid-treatment or other suitable methods. However, these compounds are not of themselves gasoline gum inhibitors except to a minor extent, so that they do not result in a gasoline or improved stability except when metal compounds are present therein.

However, the usual method or application is to add both the suppresser and the gasoline gum inhibitor simultaneously. The resulting induction period is'usually the same or slightly increased over that obtainable with the inhibitor alone in a gasoline tree or metal compounds. The suppresser may be dissolved in the gasoline gum inhibitor. As a rule, smaller amounts or the suppresser are required than of the gum inhibitor, so that a relatively minor amount of the suppresser may be added to the inhibitor, say for example, less than 50% of the total mixture.

The following example is given to illustrate 4. A method of suppressing the catalytic eflect of metal compounds on gum formation in Olefin-- containing distillate which comprises adding to: said distillate a relatively minor portion of 2-hydroxy-l-naphthaldehyde-ethanolamine.

5. A method of suppressing the catalytic effect of metal compounds on gum formation in olefin-- containing distillate which comprises adding: thereto a relatively minor portion of a gumv iii-- hibitor and a second portion of a condensation. product of an orthohydroxy aromatic aldehyde: and-a primary alkanol amine.

6. A process for suppressing the catalytic efl'ectof metal compounds on gum formation in 01min containing distillate which comprises thereto a compound having the following generail formula:

the usefulness of the invention, but should not be construed as limiting it to the compounds shown therein.

A Pennsylvania cracked gasoline containing 1 mg. of copper per liter of gasoline had an induction period oi. 35 minutes which increased upon the addition of 0.01% of N-butyl aminophenol to 85 minutes. When the various compounds of this invention were added to the inhibited gasoline in amounts of 0.01%, the induction period was increased as indicated in the following table. The induction period was measured by the well-known oxygen bomb induction period test method.

Oxygen- Per cent I Su presser Per N 9 cent aminoperiod phenol minutes N one 0.00 v 35 o 0.01 85 o-Hydroxy-benzal-ethanoiamine 0. 01 0.01 200v 2-hydro -l-'naphthaldehyde eth- 0.01 0.01 285 anola ne 2 hydroxy 1 naphtbaldehyde, l

amino-i propyl-2 pentanol 0. 0i 0. 01 105 o-Hydr -benzal -2 amino -2 methyl l,3,-propanediol 0.01 0.01 838 I claim as my invention: 1. A process for suppressing the catalytic eflect of metal compounds on hydrocarbon distillate 4 comprises adding to said distillate a relatively minor portion of a condensation product of an orthohydroxy poly-nuclear aromatic aldehyde and a primary alkanol e.

wherein R is hydrogen or a substituent group '4 and wherein R is an alkylene group.

"I. A process for suppressing the effect of metal compounds on gum formation in olefin-contain ing distillate which comprises adding to saididi's tillate a condensation product of an orthohy droxy aromatic aldehyde with a primary alkanoii amine in an amount within the limits of approximately 0.0001-0.01

8. An inhibitor 0'! gum formation in'crackedgasoline comprising essentially a mixture of a: gasoline gum inhibitor with a condensation product of an orthohydroxy aromatic aldehyde and a primary alkanol amine.

I 9. An inhibitorot gum formation in cracked gasoline comprising essentially a mixture oi. a gasoline gum inhibitor with a condensation product of an orthohydroxy mono-nuclear aromatic aldehyde and a primary alkanol amine.

10. An inhibitor of gum formation in cracked gasoline comprising essentially a mixture of a gasoline gum inhibitor with a condensation product of an orthohydroxy poly-nuclear aromatic aldehyde and a primary alkanol amine.

11. An inhibitor 01 gum formation in cracked. gasoline comprising essentially a mixture of a gasoline gum inhibitor with a condensation prod-' uct of an orthohydroxy aromatic aldehyde and a primary alkanoi amine having the general formula:

wherein R is hydrogen or a substituent group and wherein R. is an alkylene group.

'12. An inhibitor of gum formation in cracked gasoline comprising essentially a mixture of a gasoline gum inhibitor with a condensation product'oi' any orthohydroxy aromatic aldehyde and a primary alkanol amine having the general formula:

wherein R is hydrogen or a substituent group and wherein R is an alkylene group.

13. An inhibitor of gum iorrnation in cracked gasoline comprising essentially a mixture of a line gum inhibitor with a relatively minor portion of z-hydroxy-l-naphthaldehyde-ethanolamine.

14. A suppresser for the catalytic effect of metal compounds on gum formation in stacked gasoline which comprises a mixture of an N-substituted amino-phenol with a condensation product of an orthohydroxy aromatic aldehyde and a primary alkanol amine.

15. A suppresser for the catalytic effect of metal compounds on gum formation in cracked gasoline which comprise a mixture 01' a wood tar distillate gasoline gum inhibitor boiling within the range of approximately 240-280 C. and a condensation product of an orthohydroxy aromatic aldehyde with a primary alkanol amine.

16. Method of stabilizing gasoline containing traces of metallic compounds catalytically active to accelerate oxidation comprising adding thereto a small quantity of suppressor compound having the formula CH=NROH where R is alkylene.

17. Method of stabilizing gasoline containing traces of metallic compounds catalytically active to accelerate oxidation comprising adding thereto a small amount of a hydroxy aromatic com-' pound containing the radical CH=N-R0 H directly atached to the aromatic ring and in which R is an alkylene group, the hydroxy group of the aromatic nucleus being in the ortho position with respect to said radical.

18. Motor fuel comprising olefinic gasoline and a relatively small amount of a condensation product of an orthohydroxy aromatic aldehyde and a primary alkanol amine.

19. Motor fuel comprising oleflnic gasoline and a relatively small amount of an hydroxy aromatic compound containing the radical directly attached to the aromatic ring and in which R is an alkylene group, the hydroxy group of the aromatic nucleus being in the ortho position with respect to said radical.

radical.

J QSEPH A. CHENICEK. 

